In the assembly of electronic devices, integrated circuit chips are enclosed alone or with other devices in a package having a plurality of leads extending therefrom. The industry seems trending toward an increasing number of such leads while the packages are being kept as small as possible to conserve space in service. Consequently, leads are becoming more densely arranged and adapting them for service connection has become a significant problem.
One method of providing densely arranged leads for assembling such an electronic device is to employ a carrier tape preferably made of conductive material. The leads are conventionally formed therein in clusters by photolithography and etching. The tape is indexed for bonding a chip and/or other device to the lead clusters and often a second bonding takes place to stiff leads in another lead frame, such stiff leads being insertable into a P-C board.
The packaging of an assembled device in protective material also typically takes place while an assembled device is still in a lead frame. Thereafter, each device is separately detached from the lead frame environment and leads are usually bent, shaped or otherwise adapted for service connection.
In one popular, lineally leaded package, the leads are aligned in two rows causing the device to be referred to as a dual inline package (DIP). With an increasing number of leads now being used, a problem with a DIP package is that it tends to become so long that service space is used inefficiently.
In another scheme, the leads are arranged in four rows extending from four sides of a typically square package sometimes referred to as a "Mini-Quad." Now the number of leads in a Mini-Quad range up to about 60 or 70 and heavier tape material is used without a second bonding to make leads which are adapted for surface mounting on a substrate. It will be appreciated that detaching such a package from a tape and adapting such a dense arrangement of leads for service while maintaining isolative spacings therebetween is a difficult task.